1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 6c7151edd715..b0e2c4847a5d 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -110,16 +110,19 @@ static void pty_unthrottle(struct tty_struct *tty)
 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 {
         struct tty_struct *to = tty->link;
+        unsigned long flags;
 
         if (tty->stopped)
                 return 0;
 
         if (c > 0) {
+                spin_lock_irqsave(&to->port->lock, flags);
                 /* Stuff the data into the input queue of the other end */
                 c = tty_insert_flip_string(to->port, buf, c);
                 /* And shovel */
                 if (c)
                         tty_flip_buffer_push(to->port);
+                spin_unlock_irqrestore(&to->port->lock, flags);
         }
         return c;
 }